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Mike G.
Mike G., Master Electrician
Category: Electrical
Satisfied Customers: 7667
Experience:  Proven Professional 48 years Experience
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Outdoor motion sensor light problem... There are two bulbs.

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Outdoor motion sensor light problem... There are two bulbs. One bulb went out a while back. When I tried to replace it, the new one would not light up-I let it be, thinking maybe my original wiring setup had come loose or something, but I didn't want to
deal with it and just settled for having the one that was still working in the meantime. Eventually, the second bulb stopped working. When I tried to replace both, neither would light up. I finally got up there and opened up the electrical box to check for
loose connections or any other indicators that would lead me to the problem, but everything was still in tact. Next, I removed the used, but still working bulbs from a second motion-sensor light and installed them in the other light, and they turned on. I
then put brand new bulbs in the second light (the one I had just borrowed the used bulbs from), but they will not light up. In both lights, I can hear a click when flipping the light switch on and off, but neither will work with the new bulbs installed. Both
only work with the used bulbs from the second light. So now I am totally dumbfounded. How does it happen that each light will work with a used set of bulbs and not with a brand new set? The only difference between the two sets of bulbs is that the used ones
are 50W and the new ones are 100W, but I don't see how that would be a problem given each fixture is labeled with "max 150W." I attempted a temporary fix, installing only one of the used bulbs in each light so that I would at least have some light, but when
I did that, neither of the single bulbs would light up. Again, I hear the clicking when the switch is flipped on, but no light from the bulbs. Any ideas of what is causing my issue?
Did you check to see if the nonworking lamps worked in another fixture?
Customer: replied 4 years ago.
No. What are your thoughts for how this might help the troubleshooting?I'm thinking that wouldn't tell me much, since the used bulbs from the second fixture worked in both fixtures, but I wouldn't be surprised if I'm overlooking something.
The lamps may be bad. Being new doesn't mean they are good. Check it.
Customer: replied 4 years ago.
That makes sense, but I still don't understand something...Why do you suppose the setup of one bulb in each fixture doesn't work? Especially since the bulbs I used in that setup both lit up when installed together in each fixture?
Recently for energy conservation a watt limiter has been required on ceiling fan but I' m not aware it being changed for motion detector lights. Check the fixture labeling for a lamp max.
Customer: replied 4 years ago.
That first question must've been a little tough to follow...sorry for the confusion. I did mention, though, that both fixtures are marked with "max 150W," so that possibility was already eliminated.Any other ideas or are you as puzzled as I am?
My conclusion would be that the photo cell would be the problem. To verify fly, bypass it to see if the pair of lamps function.
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